On a table, how do you fill WHOLE cell with the color? I adjusted the width to 100% but it still has a very small portion inside the border that is not filling in with my "#00ff00" color. Any suggestions??

What border? You specfied no border on your table. I suspect that if you turned on the border you'd see that the area you're saying is inside the border is actually outside your table entirely. You may be looking at the page margin (minimum distance it keeps content from the browser edge).